A. Field of the Invention
The present invention relates to hot tubs in which a vigorous stream of air is pumped into the water. It is especially useful for highly decorative tub installations where the air pump is to be housed in close proximity to the tub.
B. Description of the Art
In recent years, there has been an increasing interest in large bathing tubs which are commonly known as hot tubs or spas. These spas are filled with hot water to a level sufficiently high that a bather can be immersed in the water up to the neck while sitting upright in the tub. They are often large enough to accommodate several people, and they are generally marketed for home use and enjoyment. An especially important feature of these tubs is that they allow a vigorous stream of air to be pumped into the water so that the water provides a massaging action against the bather's skin.
A considerable portion of the expense involved in the construction of such spas goes into the support system associated with the spas. To minimize this cost, it is desirable to house the air pump and other spa support accessories as close as possible to the spa (thus eliminating much connecting piping and some of the costs of hiding the piping).
Spas designed for outdoor installation are often mounted in redwood surrounds which are large enough so as to provide some space between the outer walls of the spa and the inner walls of the surround for placement of the support system required for the operation of the spa. The surround will then serve to hide and protect accessories such as the pump, while cutting down on the length of piping that is required between the air pump and spa.
However, many safety codes require that when an air pump for a spa is connected by a pipe to the spa, the pipe must include a loop (a "Hartford" loop) which is of a sufficient height so as to make it exceedingly unlikely that water will be able to back up into the air pump from the spa. The required height of the loop is higher than the height of a conventional decorative spa surround.
Because of this, a spa designer would have to leave an exposed Hartford loop pipe somewhere around the tub above the surround (if the designer did not want to accept the cost of placing the air pump outside of the surround and some distance from the tub, or of constructing a separate housing for the Hartford loop). An exposed Hartford loop pipe is unsightly. Also, it raises an additional risk of accident (e.g., a user of the tub might trip over or bump against an exposed Hartford loop pipe). Thus, it can be seen that a need has existed for an improved way to protect an air pump that is housed in a spa surround from water backflows, without sacrificing the decorative appearance of the installation, incurring unnecessary costs, or exposing the tub user to an unnecessary risk of injury.